I am using SketchUp Pro 2017, sorry I'll change that in my profile, thanks for reminding. And the dwg file I am using is saved as AutoCAD 2000 version. I am just opening SketchUp and click on file>import and then select the dwg file. The file is 17 MB so the forum didn't let me upload it.
I tried the Zoom Extents and now I can see the imported file, thanks a lot. However the program gets super slow and it makes it too hard to work on my file. Do you have any suggestions on how to reduce the file and fasten sketchup?